Trimming mechanism for sewing machines



June 21, 1938. K `V F. A. Kucr-:RA 2,121,526

. TRIMMING MECHANISM FOR SEWING MACHINES Filed Sept. 9, 1936 5 Sheets-Shee 1 fry-@IQ Z #www 231 29 Hummm! 1 W1TNbxnEs- INVENTOR:

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June 2l, 1938. F. A. KucERA v 2,121,525

TRIMMlNG MECHANISM FOR SEWING MACHINES Filed sept. 9, 195e 3 sheets-sheet 2 Y INVENToRf Iicmlc A'. Iwera',

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WITNESSES' F. A. KUCERA TRIMMING MECHANISM FOR SEWING MACHINES Jne 2l, 1938.

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Patented June 21, 1938 UNITED STATES TRIMMING MECHANISM FOR SEWING MACHINES Frank A. Kucera, Chica Special Machine Com poration of Illinois Application September 8 Claims.

nism wherein a movable cutting blade having an aligning heel pendent from a beveled cutting edge, passes up and down through the work support of the sewing machine, and by cooperation with a fixed blade having a cutting edge substantially level with the work support, trims the fabric which is being seamed in the machine. In such trimming mechanism, as heretofore constructed, the aperture provided in the work support for passage of the movable blade corresponded in size with the lcross section of said blade. ance was left between the beveled face of the cutting edge of the movable blade and the corresponding side of the aperture, with the result that the raw edge of the trimming would often be caught and pack behind the heel of the movable blade.`

My invention is directed toward precluding the contingencies just mentioned, which objective I realize in practice, as hereinafter more fully disclosed, through provision of a stripper in the form of a plate which is recessed into and Vsubstantially fills an opening in the work support of the machine in the region of the flxed'cutting blade, said plate having a notch in one of its side edges for passage of the heel of the movable cutting blade, and an edge portion adjacent said notch, which, under the action of a spring influential upon the plate, is maintained in engagement with the beveled face of said `movable blade, with consequent avoidance of a clearance i in which the raw edges of the trimming might catch.

Another objectof my invention is to attain the foregoing advantages in .a stripper which also functions as a guide to deflect the trimmed portion of the fabric awayk from 'the needle or 1 needles of the machine.

Other objects and attendant advantages will appear from the following detailed description of the attached drawings, wherein Fig. I shows in elevation, the front end of a sewing machine conveniently embodying the trimming mechanism of my invention.

Fig. II is a fragmentary sectional viewv taken as indicated by the arrows II-II in Fig. I.

, Fig. III is a fragmentary perspective view showing portions of the work support of the `machine and the trimming mechanism.

Fig. IV is a perspective view of the combined stripper and deflecting guide for theportion of As a consequence, a considerable clear- PATENT oFFicE go, Ill., assignor to` Union pany, Chicago, Ill., a cor- 9, 1936, Serial No. 99,915

(Cl. 112-12Z) the fabric severed by the trimming mechanism. Fig. V is a detail sectional view taken as indicated by the arrows V-V in Fig. II.

Fig. VI is a fragmentary view corresponding to Fig. II with the needles, the presser foot and the looper of the sewing machine removed so as to expose important parts of the trimming mechanism which would otherwise be hidden.

Fig. VII is a view like Fig. VI with the parts in a diierent position; and

Figs. VIII and IX are detail perspective views taken as indicated respectively by the arrows VIII-VIII and IX-IX in Figs. VI and VII, and drawn to a larger scale.

VThe sewing `machine herein illustrated by way of example is of the at bed type with a hollow base I which aiords a horizontal work supporting surface 2, and with an arm 3 which overhangs the work support and terminates at its free end in a guide head 4 for a needle bar 5.4i()

Confined to vertical movement in the head 4 adjacent the needle bar 5 is a presser bar 6 whereto la presser foot 'I is secured `at the lower end. Set into the work support 2 is a throat plate B which is secured by screws indicated at 9, and which is provided with the usual elongate slots I for protrusion of the toothed portions of the feed dog IIV and also with apertures I2 for` the passage ofthe needles I3 (of which there are three in the present instance) at the lower end of the needle bar 5. Cooperating with the needles I3 above the work support 2 is a cover thread looper I5 (Figs. I'and II), which, through parts (not illustrated) within a housing I6 attached to i the head 3, is actuated by an arm I7 on a rock shaft Ill` which exten-ds longitudinally of the back of the overhanging arm 3. suitably journaled within the hollow base I of the machine frame is a longitudinal drive shaft I9 from which the stitch-forming and feeding instrumentalities of the machine derive m-otion either directly or indirectly in av well known manner. The arrangement of the needles and looper of the illustrated machine is generally like that shown in U. S. PatentNo. 1,528,499 of March 3, 1925 for producing a seam like that shown in U. S. Pat'- kent No. 1,473,636 of November 13, 1923, both granted to J. R. Moffatt.

'I'he trimming mechanism with which the present invention is more especially concerned includes a fixed blade 20 which is secured to the frame of the machine and which lies along the recessed edge portion 2| of the throat plate 8 with its cutting edge at about the level of the top of thel Work support 2, see Figs. VIII and IX.

Cooperating with the xed blade is a movable cutting blade 22, which in this instance, has the form of an arc and which is provided with a heel 23 whereby its beveled cuttingedge 25 is maintained in alignment with the cutting edge of the fixed blade when said movable blade is in elevatednposition as shown in Figs. I and III. The movable blade 22 is secured with capacity for adjustment along the curvature of its arc in a transversely slotted head 26 at one end of a rod 21which is axially free in spaced guide portions 28 at the upper end of a supporting rocker arm 29. A'helical spring 30 surrounding the rod 21 and compressed between an adjustable collar 3l on said rod and one'of the guide bosses 28 serves to keep the movable blade 22 laterally in yielding cutting engagement with the xed blade 20, rotation of said rod being prevented through sliding engagement of a collar 3l thereon with a guide edge 32 at the swinging end of the arm 29. The rocker arm 29 is ulcrumed at 33 on a bracket 34 secured to the machine base I and may be actuated as shown in Figs. I and II, through a strap arm 35, from an eccentric 36 on the shaft I9 hereinbefore referred to.

As the fabric F (Fig. II) is progressed transversely of the work support 2 by the feed dog I I, its right-hand edge is trimmed by cooperation of the cutting blades 2U and 22 in advance of the needles I3 (as considered in the direction of feeding indicated by the arrow in Fig. II), the trimmed strip S being deflected laterally away from said needles by a combined stripper and deflecting guide which is generally designated by the numeral 31 and shown in perspective by itself lin Fig. IV. As illustrated, this combined :stripper and guide 31 -has a flat plate-like stripper portion V38, fromwhich extends an upwardly and laterally directed guard portion 39 for restraining the trimming S. From Figs. II, III, VI and VII, it will be noted that the flat portion 38 of the guide 31 lies adjacent the right-hand or inner side of the throat plate 8 with its top surface -iiush with that of said throat plate, and that it occupies a depression 40 of substantially the same size and configuration along the contiguous edge of Aa supplemental removable cover section 4I which closes an opening 42 in the work support 2, the top of said supplemental plate being in turn flush with said work supporting surface and the throat plate. As shown in Fig. V, the cover section 4I rests on ledges 43, 44 along opposite vside edges of the opening 42 in the work support,

its left-hand edge being held down by a tongue '.45 which underreaches the ledge 43, and its rightha-nd edge secured by a sliding latch member 46 with a'spring tongue 41 which underreaches the ledge 44. At one end, the plate portion 38 of the deecting guide 31 is pivotally connected to the ,cover plate 4I, by a screw 48, with capacity for limited horizontal swinging movement within the recess 4l) relative to the throat plate 8. By means of -a finger spring/50 anchored at 5I inthe bottom of the cover plate-4I near the ledge 43 and engaging a screw stud 52 depending from the portion 38 of the deflecting guide through a clearance slot 53 at said ledge, the guide is yieldingly urged leftward with the inner edge of a frontal recess` 55 (Fig. IV) near its swinging end normally engaging the heel 23 of said movable cutting blade 22 as shown in Fig. VI. Immediately adjacent the recess 55 the plate 38 of the defi'ecting guider31 has an edge portion 56 which is adapted to cooperate with the beveled face of the mov- ,able cutting blade 22, and beyond said edge portion 56, a toe projection 51 which normally reaches substantially to the edge 2I of the throat plate 8 and lls that part in the opening 42 of the work support 2 forward of the xed cutting blade 20. From the described construction, it will be apparent that each time the blade 22 descends, the bevel of itscutting edge 25 engages the edge portion 56 of the guide 31 as shown in Fig. IX and by camming action therewith, the guide is displaced slightly to the right from the position of Fig. VI to the position of Fig. VII in opposition to the spring 50. As a consequence, the stripper plate 38 of the deflecting guide 31 will prevent the raw edges of the severed fabric strip from being pinched and caught behind the heel 23 of the movable knife 22. At the same time, the upstanding wall of the guard portion 39 of the deflecting guide 31 will divert the trimming S laterally from the needles I3. In order to facilitate this deflecting action, the top of the plate portion 38 of the guide 31 is gouged as at 58 at the region where it coacts with the movable cutting blade 22, and the throat of said guide rounded at 59 at its entrant end, see Figs. VI and VII. The rounded surface 59, it will be noted, is provided by a lateral projection 68 of the guard 39 near the swinging end of the guide 31, which extends to` the notch 55, and which is vertically gouged tov form a barrier around the contiguous needle I3. The cover plate 4I and the contiguous portion of the work support 2 are recessed as at 6I and 62 respectively to provide a rearwardly-extending channel for directing the trimming S after it leaves the guide 31.

Having thus described my invention, I claim:

1. Trimming mechanism for sewing machines, comprising a xed blade along one edge of an opening in the work support of a sewing machine with its cutting edge substantially at the level of the top of said work support; a cooperating movable cutting blade actuated from Yabove the work support to trim fabric being sewed in the machine; a movable trimming stripper in ythe form of a plate substantially closing said opening in the region of the fixed blade and having an upwardly extending portion for deflecting the trimmings; and yielding means influential upon the stripper plate to maintain an edge of the latter in lateral contact with the movable blade.

2. Trimming mechanism f or sewing machines, comprising a xed blade along one edge of an opening in the work support of a sewing machine with its cutting edge substantially at the level of the top of said work support; a cooperating movable cutting blade actuated from above the work support to trim fabric being sewed in the machine; a pivoted trimming stripper in the form of a plate substantially closing said opening in the region of the xed blade and having an upwardly extending portion for deflecting the trimmings; and yielding means influential upon said plate in maintaining an edge of the latter in contact with the movable blade.

3. Trimming mechanism for sewing machines comprising a fixed blade along one edge of an l opening in the work support of the sewing machine, with its cutting edge substantially at the level of the top of the work support; a cooperating movable blade with. a beveled cutting edge actuated from above the work support to trim fabric being sewed in the machine; a movable trimming stripper in the form of a plate substantially closing said opening in the region of the fixed blade and having an upwardly extend- Ying portion for deflecting the trimmings; and

yielding means inuential upon the stripper plate to permit camming action between an edge portion of said plate and the beveled face of the movable blade incident to` descent of the latter in cutting.

4. Trimming mechanism for sewing machines, comprising a fixed blade along one edge of an opening in the work support of a sewing machine with its cutting edge substantially at the level of the top of said work support; a cooperating movable blade, with a beveled cutting edge, actuated from above the work support to trim fabric being sewed on the machine; a pivoted trimming stripper in the form of a plate substantially closing said opening in the region of the fixed blade and having an upwardlyextending portion for deflecting the trimmings; 'and yielding means iniiuential upon the stripper plate to permit camming action between an edge portion at the swinging end of said plate and the beveled face of the movable blade incident to descent of the latter in cutting.

5. Trimming mechanism for sewing machines, comprising a fixed blade along one edge of an opening in the work support of the sewing machine with its cutting edge substantially at the level of the top of said work support; a cooperating movable blade actuated from above the work support to trim fabric being sewed in the machine, and having a pendant aligning heel below a beveled cutting edge; a movable trimming stripper in the form of a plate substantially closing said opening in the region of the fixed blade with provision of an aperture for passage of the heel of the movable blade through the work support and having an upwardly extending portion for deecting the trimmings; and yielding means influential upon the stripper plate to permit camming action between an edge portion of said plate adjacent the aperture and the beveled face of the movable blade incident to descent of the lat ter in cutting.

6. Trimming mechanism for sewing machines, comprising a xed blade along one edge of an opening in the work support of the sewing machine with its cutting edge substantially at the level of the top of said work support; a cooperating movable blade actuated from above the work support for trimming fabric being sewed in the machine; a movable stripper and defiecting guide with a guard portion to laterally deect the trimming away from the needle of the sewing machine, and with a plate portion which substantially closes the opening in the work support in the region of the iixed blade; and yielding means influential upon the guide to maintain an edge of its plate portion in lateral contact with the movable blade.

7. Trimming mechanism for sewing machines, comprising a xed blade along one edge of an opening in the work support of the sewing machine with its cutting edge substantially at the level of the top of said work support; a cooperating movable blade actuated from above the work support for trimming fabric being sewed in the machine; a pivoted stripper and deiiecting guide with a guard portion to laterally deiiect the trimming away from the needle of the sewing machine, and with a plate portion which substantially closes the opening in the work support in the region of the xed blade; and yielding means influential upon the guide to maintain an edge of its plate portion in lateral contact with the movable blade.

8. 'Irimming mechanism for sewing machines, comprising a fixed blade along one edge of an opening in the work support of the sewing machine with its cutting edge substantially at the level of the top of said work support; a cooperating movable blade actuated from above the work support to trim fabric being sewed in the machine, and having a pendant aligning heel below a beveled cutting edge; a movable stripper and deflecting guide having a plate portion which substantially closes the opening in the work support in the region of the xed blade with provision of an aperture for passage of the heel of the movable blade through said work support, and an upwardly extending portion for delecting the trimmings and yielding means inuential upon the guide to permit camming action between an edge segment adjacent the aperture in the plate portion of said guide, and the beveled face of the movable blade incident to descent of the latter in cutting.

FRANK A. KUCERA. 

